The present invention relates to an engine including an EGR apparatus (exhaust gas recirculation apparatus) which refluxes a portion of exhaust gas from an exhaust system to an intake system as EGR gas.
Conventionally, as countermeasures against exhaust gas of a diesel engine and the like, there is known a technique for lowering combustion temperature and reducing an amount of NOx (nitrogen oxides) in exhaust gas by an EGR apparatus (exhaust gas recirculation apparatus) which refluxes a portion of exhaust gas from an exhaust system to an intake system. In an engine including this kind of EGR apparatus, there is also known a technique for correcting an opening degree of an EGR valve existing in a refluxing passage which connects the exhaust system and an intake system to each other based on differential pressure (differential pressure of intake/exhaust gas) between intake pressure and exhaust pressure (see Patent Documents 1 and 2 for example).